No, LLMs are not used (nor would they be allowed). As for whether you would consider OCR to be AI, then... possibly?
My bro-in-law supported his family as a freelance editor for years while my sister was doing the "maternity leave" thing so I know there's a non-trivial amount of work that goes into book editing. Cutting out some of that human labor seems like a good thing for a volunteer project.
the vast majority of textual tooling is regex-galore, but there is also automated epub tooling in there too